Preforms of plastic such as for example polyethylene terephthalate (PET), polypropylene (PP) etc. are used in particular in the drinks industry for the production of containers, for example bottles. The preforms are supplied to the container handling plants which heat the preforms in a heating device in order then to expand and stretch them into plastic containers in a blow-mounding machine using a blow-moulding process. The plastic containers are then transported by means of a transport system to further treatment devices such as for example a cleaning apparatus, a labelling apparatus, a filling apparatus, a sorting apparatus, a packing apparatus etc.
The preforms are usually first supplied to the container processing plants unsorted. Unsorted here means that the preforms are first passed to a receiver apparatus in which, although usually preforms of the same type such as size, material etc. are present, the preforms can be oriented in any direction in relation to each other. To process the preforms in the container processing plant, the preforms must however all be aligned in a predetermined direction to each other. To this end roll sorter devices for example are used in the prior art.
US 2004/0109747 A1 describes a system for supplying preforms in particular for a container blowing machine. This system has a filling hopper, on the base of which are arranged two substantially parallel rolls which rotate about their respective axes. The gap between the two rolls is dimensioned such that it is greater than the diameter of the body of the preforms placed in the filling hopper but is smaller than the diameter of the neck ring of the preforms in the filling hopper. As the diameter of the body of the preforms is smaller than the diameter of the neck ring of the preforms, preforms which fall through the gap with their body first are suspended by their neck ring on the two rolls. Preforms which for example remain lying completely on the rolls are pushed off the rolls via a pusher wheel arranged above and transverse to the axis of the two rolls so that the two rolls only transport preforms which are aligned next to each other in one direction.
However, seized preforms cannot be removed from the two rolls with such a roll sorter device.
It may be desirable to provide an improved roll sorter device and an improved sorting method for sorting preforms and a transport device with such a roll sorter device that can economically also remove seized preforms from the two rolls of the roll sorter device.